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We present a fast algorithm for evaluating the (non-smooth) solution of the free-space two-dimensional (2D) scalar wave equation with many point sources, each with a high-frequency band-limited time signature. Such an algorithm is key to an…

Numerical Analysis · Mathematics 2026-04-09 Nour G. Al Hassanieh , Leslie Greengard , Alex H. Barnett

We introduce a new arbitrarily high-order method for the rapid evaluation of hyperbolic potentials (space-time integrals involving the Green's function for the scalar wave equation). With $M$ points in the spatial discretization and $N_t$…

Numerical Analysis · Mathematics 2025-07-11 Nour G. Al Hassanieh , Alex H. Barnett , Leslie Greengard

This paper presents a new methodology for the solution of problems of two- and three-dimensional acoustic scattering (and, in particular, two-dimensional electromagnetic scattering) by obstacles and defects in presence an arbitrary number…

Numerical Analysis · Mathematics 2017-08-23 Oscar P. Bruno , Carlos Pérez-Arancibia

This paper introduces a new Windowed Green Function (WGF) method for the numerical integral-equation solution of problems of electromagnetic scattering by obstacles in presence of dielectric or conducting half-planes. The WGF method, which…

Computational Physics · Physics 2015-08-05 Oscar Bruno , Mark Lyon , Carlos Perez-Arancibia , Catalin Turc

This paper proposes a frequency/time hybrid integral-equation method for the time dependent wave equation in two and three-dimensional spatial domains. Relying on Fourier Transformation in time, the method utilizes a fixed…

Numerical Analysis · Mathematics 2020-04-30 Thomas G. Anderson , Oscar P. Bruno , Mark Lyon

The plane wave method is most widely used for solving the Kohn-Sham equations in first-principles materials science computations. In this procedure, the three-dimensional (3-dim) trial wave functions' fast Fourier transform (FFT) is a…

Computational Physics · Physics 2018-01-17 Xingyu Gao , Zeyao Mo , Jun Fang , Han Wang

Wave equations are fundamental to describing a vast array of physical phenomena, yet their simulation in inhomogeneous media poses a computational challenge due to the highly oscillatory nature of the solutions. To overcome the high costs…

Machine Learning · Computer Science 2026-03-17 Yiyang Cai , Zixuan Qiu , Yunlu Shu , Jiamao Wu , Yingzhou Li , Tianyu Wang , Xi Chen

We have developed an algorithm for transferring radiation in three-dimensional space. The algorithm computes radiation source and sink terms using the Fast Fourier Transform (FFT) method, based on a formulation in which the integral of any…

Astrophysics · Physics 2009-11-07 Renyue Cen

This paper is concerned with fast and accurate computation of exterior wave equations truncated via exact circular or spherical nonreflecting boundary conditions (NRBCs, which are known to be nonlocal in both time and space). We first…

Numerical Analysis · Mathematics 2011-09-27 Li-Lian Wang , Bo Wang , Xiaodan Zhao

Although Fourier series approximation is ubiquitous in computational physics owing to the Fast Fourier Transform (FFT) algorithm, efficient techniques for the fast evaluation of a three-dimensional truncated Fourier series at a set of…

Numerical Analysis · Mathematics 2017-03-08 Marco Caliari , Simone Zuccher

We introduce a fast algorithm for computing sparse Fourier transforms supported on smooth curves or surfaces. This problem appear naturally in several important problems in wave scattering and reflection seismology. The main observation is…

Numerical Analysis · Mathematics 2008-01-11 Lexing Ying

Over the last two decades, several fast, robust, and high-order accurate methods have been developed for solving the Poisson equation in complicated geometry using potential theory. In this approach, rather than discretizing the partial…

Numerical Analysis · Mathematics 2024-09-19 Fredrik Fryklund , Leslie Greengard , Shidong Jiang , Samuel Potter

This paper is concerned with three-dimensional acoustic wave scattering in two-layer media, where the two homogeneous layers are separated by a locally perturbed plane featuring an axially symmetric perturbation. A fast novel boundary…

Numerical Analysis · Mathematics 2024-12-17 Hangya Wang , Wangtao Lu

A variety of problems in acoustic and electromagnetic scattering require the evaluation of impedance or layered media Green's functions. Given a point source located in an unbounded half-space or an infinitely extended layer, Sommerfeld and…

Numerical Analysis · Mathematics 2015-07-23 Jun Lai , Leslie Greengard , Michael O'Neil

This paper presents a windowed Green function (WGF) method for the numerical solution of problems of elastic scattering by "locally-rough surfaces" (i.e., local perturbations of a half space), under either Dirichlet or Neumann boundary…

Computational Physics · Physics 2021-02-03 Oscar P. Bruno , Tao Yin

This paper presents a class of boundary integral equation methods for the numerical solution of acoustic and electromagnetic time-domain scattering problems in the presence of unbounded penetrable interfaces in two-spatial dimensions. The…

Computational Physics · Physics 2019-10-02 Ignacio Labarca , Luiz M. Faria , Carlos Pérez-Arancibia

We consider the expansion of wave packets governed by the free Schr\"odinger equation. This seemingly simple task plays an important role in simulations of various quantum experiments and in particular in the field of matter-wave…

Computational Physics · Physics 2023-03-17 Jan-Frederik Mennemann , Sebastian Erne , Igor Mazets , Norbert J. Mauser

We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain,…

Chemical Physics · Physics 2023-07-10 Jason Kaye , Alex Barnett , Leslie Greengard , Umberto De Giovannini , Angel Rubio

We present a fast algorithm for computing the diffracted field from arbitrary binary (sharp-edged) planar apertures and occulters in the scalar Fresnel approximation, for up to moderately high Fresnel numbers ($\lesssim 10^3$). It uses a…

Instrumentation and Methods for Astrophysics · Physics 2020-12-18 Alex H. Barnett

We introduce a Fourier-based fast algorithm for Gaussian process regression in low dimensions. It approximates a translationally-invariant covariance kernel by complex exponentials on an equispaced Cartesian frequency grid of $M$ nodes.…

Computation · Statistics 2023-05-19 Philip Greengard , Manas Rachh , Alex Barnett
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